We conducted a photographic survey to examine the differences in impressions that junior high school students receive from classroom interiors with varying amounts of wood ratios, as well as the structure of their evaluations. The students were shown photographs reflecting three wood ratio patterns of the interior elements (ceilings, walls, and floors): all wood, half wood, and no wood. The students evaluated the photographs using the semantic differential method based on a seven-grade scale with 21 adjective pairs. The results of the factor analysis showed a three-factor structure. Factor 1: “preference of the space”; factor 2: “school-likeness of the space”; and factor 3: “physical characteristics of the space.” The factor 1 score increased with an increase in the wood ratio. The factor 2 score remained unchanged, whereas the factor 3 score changed with the presence or absence of wood. This study suggests that the wood ratio of classroom interiors affects the visual impressions of junior high school students.

This study aimed to assess the machining properties of fast-growing trees in Japan, by measuring the cutting force while sawing workpieces of different fast-growing trees into 5 mm-thick boards using a band sawing machine with a carriage. The tested tree species which were tested included Cunninghamia lanceolata, Corymbia citriodora, six species of Eucalyptus, Liquidambar formosana, Liriodendron tulipifera, Melia azedarach and Cryptomeria japonica. The sawing process was performed at feed speeds of 0.17, 0.33, 0.50, and 0.67 m/s. The results showed that the cutting force parallel to the cutting direction increased with increasing basic density of the workpiece as well as the feed speed. However, no clear relationship was observed between the cutting force normal to the cutting direction, the force parallel to the feeding direction, and the basic density of the workpiece. Specifically, while sawing C. lanceolata grown in Shizuoka Prefecture and C. japonica, the cutting force normal to the cutting direction remained constant at approximately 30 N, regardless of the feed speed. In the case of M. azedarach grown in Kumamoto Pref., the cutting force normal to the cutting direction increased, whereas it decreased for C. lanceolata grown in Chiba Pref., M. azedarach grown in Fukuoka Pref., L. formosana, L. tulipifera, C. citriodora, and all tested species of Eucalyptus as the feed speed increased. Furthermore, we measured the power consumption while sawing workpieces of C. lanceolata grown in Shizuoka Pref., M. azedarach grown in Fukuoka Pref., L. tulipifera, and three species of Eucalyptus into 30 mm-thick boards. It was observed that the power consumption was higher for species with larger cutting forces parallel to the cutting direction.